Skincare compositions, sometimes including cosmetics, are daily necessities in modern human life. All types of skincare compositions including moisturizers, wrinkle removers, freckle removers, whitening, and acne treatments are used to improve quality of life and solve the problems of aged skin due to damage, degeneration and decreased skin function, etc. Various chemicals, extracts from animals and plants, tissue extracts of human origin and polypeptides of recombinant protein have been used as additives and active ingredients to make skincare compositions. Among these are, human epidermal cell growth factor (EGF), fibroblast growth factor (FGF) and human serum albumin (HSA) from human origin or recombinant gene expression product. As cytokines are amino acids and peptides, their shelf life and half-life in plasma and in exposing on skin surface are short. Therefore, it is necessary to add protective agents to prolong their shelf life and effective half-life in vivo. In the Chinese Patent Application 200710057571.9 of Yu, Zailin, it is shown that protein fusion technology of fusing the human skin cell growth factors with HSA and validates prolongs the half-life of these cytokines.
Human serum albumin is a soluble, monomeric protein which comprises about one-half of the blood serum protein. Albumin functions primarily as a carrier protein for steroids, fatty acids, and thyroid hormones and plays a role in stabilizing extracellular fluid volume. Albumin is a globular non-glycosylated serum protein of molecular weight 65,000 with 585 amino acids. Proalbumin, is cleaved in the Golgi vesicles to produce the secreted albumin. HSA has 35 cysteines; in blood this protein monomer has 17 disulfide linkages (Brown, J. R. “Albumin structure, Function, and Uses” Pergamon, N.Y., 1977). At present, albumin for clinical use is produced by extraction from human blood. The production of recombinant albumin (rHSA) in microorganisms has been disclosed in EP 330 451 and EP 361 991, and in China patent ZL2004010057313.7 of Yu, Zailin. Albumin is the most abundant plasma protein in human blood with 40 g per liter, and with a high plasma half-life 14-20 days.
When growth factors are fused with albumin, to form compounds according to this invention the fusion protein has the advantage of resisting enzymatic degradation in vivo and prolonged sustainable half-life in vivo and shelf life in vitro. Also after fusion, it allows use of a high dosage of fused cytokine, and use of the fusion protein produces less toxicity than occurs when the cytokine is used alone.
Albumin from human blood or recombinant human serum albumin has been used in skincare. For example, human serum albumin was used as an ingredient in the anti-wrinkle product disclosed in EP 0180968A3, and used in skin cleaners and shampoos are disclosed in PCT application WO02/49671A1. It was described in detail in U.S. patent application Ser. No. 10/446,562 that combination of human serum albumin and Bacillus botulinus was used as therapeutic skincare. PCT application WO01/91713A1 describes the use of human serum albumin from transgenic animal in skincare compositions. U.S. Pat. No. 5,948,609 disclosed the whole length or fragment or modified albumin in skincare compositions. Chinese Patent applications CN02111695, CN1090753, CN93105601.2 and CN01810411.8 describe human albumin used as an additive and a protective agent in skincare. Chinese Patent application CN200610081498.4 focused on describing formulation and procedure in production of recombinant albumin and yeast ferment for moisturizing skin, smoothing wrinkles and whitening skin.
Albumin is also often used as stabilizer in pharmaceutical formulation, especially in biologicals.
With gene recombinant engineering technology, a fusion protein can be expressed in yeast linking a therapeutic protein gene product and human serum albumin having improved stability and half life for the therapeutic protein in plasma and storage stability to achieve a long-lasting effect. The technology platform for the making of such fusion proteins (such as the modified protein drug of this invention (in vivo is cited as a reference here), which has been disclosed in Chinese Patents ZL02142881.6 and ZL200410042814.8 by Yu, Zailin and Fu, Yan). The human serum albumin fusion protein of this invention is used in making skincare compositions with improved cytokines's half-life and has an optimal clinical effect in the application of novel gene skincare products.
Procedures for formulating and producing skincare compositions comprising these fusion proteins are the same as the known methods of skincare composition production described in the literature of the field. The book “Cosmetics-principals, formulation and production procedure” is a main reference, written by Wang Peiyi, 2nd edition 2006, published by Chemistry Industry Press.